Polymeric disk-shaped valve members have many industrial applications. For example, they can be used in air conditioners, ventilators, heat pumps, and reciprocating piston type compressors including refrigeration compressors. Both single and multi-cylinder compressors employ these valve members. Compressors are used both in the home and in large scale industrial applications. In these compressors, the typical function of the discharge valve member is to be part of the valving unit which allows fluid to flow both into and out of a compressor chamber.
In a typical compressor, the valve member is exposed to demanding environments and therefore requires excellent chemical resistance, high-temperature resistance, and overall fatigue durability. The valve members are usually made of polymeric resins although metals can also be used. Although polymeric materials ("resins") are advantageously light-weight, many polymeric materials cannot survive these demanding environments. This limitation in material selection severely hampers the ability to improve the performance of these valve members.
A cross-sectional view or a conventional polymeric disk-shaped valve member used in compressors is shown in FIG. 1 together with a valve seat. This sectional view illustrates that in conventional practice the cross-sectional thickness of the valve base is not always uniform. Rather, the base thickness is greater in the middle than at the periphery. This middle bulge improves valve strength and allows stresses on the valve member to be accommodated. Such non-uniformity, however, can cause distortion during the molding and curing process so that secondary machining becomes necessary. Secondary machining is undesirable because it increases production costs. The prior art valve member of FIG. 1 is discussed below in more detail.
In addition, valve members are needed which have good sealing properties, superior mechanical and fatigue performance, and also light weight. Light weight valves are particularly important for high speed compressors where valve inertia becomes significant. The valve may be required to move in and out over 1,000 times per minute. Also, avoidins noise is important for many compressor applications.
Various prior compressors and compressor valves have been used to address certain problems and needs. For example, U.S. Pat. No. 3,508,849 is directed to a suction-discharge valve for a high pressure fluid compressor. In addition, U.S. Pat. No. 3,814,546 is directed to a seal assembly for air compressor valves which is designed to not distort. Multiple sealing rings are shown as part of a valve cage. U.S. Pat. No. 4,445,534 (and related patents, U.S. Pat. Nos. 4,478,243 and 4,368,755) is directed to a polymeric discharge valve member for use in a gas compressor. Both reed-type suction and conventional ring-type suction valve assemblies are disclosed. These patent references, however, fail to address any of the aforementioned problems and needs.